I ordered both lenses and after weeks of testing and hundreds of test, comparability and normal photos, I can say the following: It is by no means unique.
The Tamron is in all focal lengths, all panels and the complete picture sometimes more, sometimes less clearly sharper than the Carl Zeiss. Not that Carl Zeiss is blurred, but the Tamron is again sharply. For this, the Tamron has some significant Chromatic aberration of all apertures and focal lengths. When Carl Zeiss CA is virtually non-existent. CA can be but in the post also relatively easy to remove. The Carl Zeiss distorted significantly in 24 mm; more than the Tamron at 28 mm. From 35 mm but only slightly and remains up to 70 mm that. The Carl Zeiss is recognized by the Lens Correction camera own and CA, vignetting and distortion are calculated out clean in the JPEGs. The Tamron, however, is officially recognized by Adobe Lightroom and two clicks later all lens errors are gone - in RAW, not only in the JPEGs! Ultimately speak size and weight for the Tamron as always-it-lens (510g vs. 955g!).
In backlit situations outshine very bright areas when Tamron but surrounding areas and sometimes the CA is so strong that thin surfaces still a purple tint have (thin branches against the sky). I also had the effect that the image was actually sharp but blurred all texture detail still in a handful of photos (300+). As one would hold a lens underwater. I could not understand the behavior. It occurred with different aperture, focal lengths and zoom levels.
AF operates in two lenses quickly and reliably. The SSM AF from Sony is of course silent, in the normal Sony Tamron AF works quietly. Vignette is also not negatively noticed in both. Both also work on full frame cameras. Both the Tamron and the Carl Zeiss are processed very valuable and are well in hand; the Tamron through the roughened surface may be a bit better.
To put my comparison into perspective: I run here pixel Pickerei at very high levels. I had to zoom in in my 24-MP images at 100% and repeatedly switch back and forth in order to identify differences. Often I had to look in the Metadata to see which lens I now have before me. Both lenses also take it easy with my prime lenses on (apart from the diaphragm). But I had to at some point decide for one.
The decision much not simply. Speak especially sharpness, official Lightroom support, weight and price of the Tamron. For Carl Zeiss is the absence of CA.
I then yet decided on the unreasonable variation and keep the expensive Carl Zeiss. Apart from the (in comparison with the Tamron) Focus the image quality is especially in extreme situations very good - not perfect, but very good. And if this is so expensive more quality up 6x, then it must be that. And 24 versus 28 mm is not to be despised.
All others I rate but, the Tamron 28-75 mm to display F / 2.8 in more detail. It is an excellent lens and ridiculously cheap for the price.
